Leads for use with implantable medical devices may be implanted in the venous, arterial, or lymphatic networks. The diameter of a microlead may be at most equal to 1.5 French (0.5 mm), and it may include a plurality of micro-cables each including: an electrically conductive core cable for connection to one pole of a multipolar generator of an active implantable medical device, and a polymer insulation layer surrounding the core cable. At least one exposed area may be formed in the insulation layer to form a detection/stimulation electrode.